Fix unicode/bytes handling for python-3

powerline/segments/vim.py

@@ -180,7 +180,7 @@ def file_scheme(pl, segment_info):
 		return None
 	match = SCHEME_RE.match(name)
 	if match:
-		return unicode(match.group(0))
+		return match.group(0).decode('ascii')
 
 
 @requires_segment_info

tests/vim.py

@@ -525,7 +525,7 @@ class _Buffer(object):
 			import os
 			if type(name) is not bytes:
 				name = name.encode('utf-8')
-			if ':/' in  name:
+			if b':/' in  name:
 				self._name = name
 			else:
 				self._name = os.path.abspath(name)